<?php

// +----------------------------------------------------------------------

// | ThinkPHP [ WE CAN DO IT JUST THINK IT ]

// +----------------------------------------------------------------------

// | Copyright (c) 2006-2013 http://thinkphp.cn All rights reserved.

// +----------------------------------------------------------------------

// | Licensed ( http://www.apache.org/licenses/LICENSE-2.0 )

// +----------------------------------------------------------------------

// | Author: liu21st <liu21st@gmail.com>

// +----------------------------------------------------------------------

namespace Think\Cache\Driver;

use Think\Cache;

defined('THINK_PATH') or exit();

/**

 * Shmop缓存驱动 

 */

class Shmop extends Cache {



    /**

     * 架构函数

     * @param array $options 缓存参数

     * @access public

     */

    public function __construct($options=array()) {

        if ( !extension_loaded('shmop') ) {

            E(L('_NOT_SUPPERT_').':shmop');

        }

        if(!empty($options)){

            $options = array(

                'size'      => C('SHARE_MEM_SIZE'),

                'temp'      => TEMP_PATH,

                'project'   => 's',

                'length'    =>  0,

                );

        }

        $this->options = $options;

        $this->options['prefix'] =  isset($options['prefix'])?  $options['prefix']  :   C('DATA_CACHE_PREFIX');        

        $this->options['length'] =  isset($options['length'])?  $options['length']  :   0;        

        $this->handler = $this->_ftok($this->options['project']);

    }



    /**

     * 读取缓存

     * @access public

     * @param string $name 缓存变量名

     * @return mixed

     */

    public function get($name = false) {

        N('cache_read',1);

        $id = shmop_open($this->handler, 'c', 0600, 0);

        if ($id !== false) {

            $ret = unserialize(shmop_read($id, 0, shmop_size($id)));

            shmop_close($id);



            if ($name === false) {

                return $ret;

            }

            $name   =   $this->options['prefix'].$name;

            if(isset($ret[$name])) {

                $content   =  $ret[$name];

                if(C('DATA_CACHE_COMPRESS') && function_exists('gzcompress')) {

                    //启用数据压缩

                    $content   =   gzuncompress($content);

                }

                return $content;

            }else {

                return null;

            }

        }else {

            return false;

        }

    }



    /**

     * 写入缓存

     * @access public

     * @param string $name 缓存变量名

     * @param mixed $value  存储数据

     * @return boolean

     */

    public function set($name, $value) {

        N('cache_write',1);

        $lh = $this->_lock();

        $val = $this->get();

        if (!is_array($val)) $val = array();

        if( C('DATA_CACHE_COMPRESS') && function_exists('gzcompress')) {

            //数据压缩

            $value   =   gzcompress($value,3);

        }

        $name   =   $this->options['prefix'].$name;

        $val[$name] = $value;

        $val = serialize($val);

        if($this->_write($val, $lh)) {

            if($this->options['length']>0) {

                // 记录缓存队列

                $this->queue($name);

            }

            return true;

        }

        return false;

    }



    /**

     * 删除缓存

     * @access public

     * @param string $name 缓存变量名

     * @return boolean

     */

    public function rm($name) {

        $lh = $this->_lock();

        $val = $this->get();

        if (!is_array($val)) $val = array();

        $name   =   $this->options['prefix'].$name;

        unset($val[$name]);

        $val = serialize($val);

        return $this->_write($val, $lh);

    }



    /**

     * 生成IPC key

     * @access private

     * @param string $project 项目标识名

     * @return integer

     */

    private function _ftok($project) {

        if (function_exists('ftok'))   return ftok(__FILE__, $project);

        if(strtoupper(PHP_OS) == 'WINNT'){

            $s = stat(__FILE__);

            return sprintf("%u", (($s['ino'] & 0xffff) | (($s['dev'] & 0xff) << 16) |

            (($project & 0xff) << 24)));

        }else {

            $filename = __FILE__ . (string) $project;

            for($key = array(); sizeof($key) < strlen($filename); $key[] = ord(substr($filename, sizeof($key), 1)));

            return dechex(array_sum($key));

        }

    }



    /**

     * 写入操作

     * @access private

     * @param string $name 缓存变量名

     * @return integer|boolean

     */

    private function _write(&$val, &$lh) {

        $id  = shmop_open($this->handler, 'c', 0600, $this->options['size']);

        if ($id) {

           $ret = shmop_write($id, $val, 0) == strlen($val);

           shmop_close($id);

           $this->_unlock($lh);

           return $ret;

        }

        $this->_unlock($lh);

        return false;

    }



    /**

     * 共享锁定

     * @access private

     * @param string $name 缓存变量名

     * @return boolean

     */

    private function _lock() {

        if (function_exists('sem_get')) {

            $fp = sem_get($this->handler, 1, 0600, 1);

            sem_acquire ($fp);

        } else {

            $fp = fopen($this->options['temp'].$this->options['prefix'].md5($this->handler), 'w');

            flock($fp, LOCK_EX);

        }

        return $fp;

    }



    /**

     * 解除共享锁定

     * @access private

     * @param string $name 缓存变量名

     * @return boolean

     */

    private function _unlock(&$fp) {

        if (function_exists('sem_release')) {

            sem_release($fp);

        } else {

            fclose($fp);

        }

    }

}